Hot-air furnace.



N0. 708,'2I5. v Patented Sept. 2, I902. C. ,H. FOSTER."

HUT AIR FURNACE. (Application filed Mar. 13, 1902.

(No Model.)

'0. H. Foster ammo 6 UNITED STATE PATENT OFFICE.

CHARLES H. FOSTER, OF OMAHA, NEBRASKA.

HOT-AIR FURNACE.

SPECIFICATION forming part of Iletters Patent No. 708,215, dated September 2, 1902. Application filed. March 13, 1902. Serial No. 98,070. (No model.)

To an whom it may concern:

Be it known that 1, CHARLES H. FOSTER, a citizen of the United States,residing at Omaha, 7 in the county of Douglas and State of'Nebraska, have invented a certain new and use- My invention consists in part in providing a combustion-chamber with two pairs of descending fiues connected by base-fines and providing said base-fines with ascending fines connected to a suitable conduit communicating with the outlet-pipe.

My invention also consists in making two of the descending fines of such a furnace shorter than the other descending fines to provide room for the conduit and connecting the ascending fines to the base fines at points nearer to the long descending fines, so as to equalize the draft.

In the accompanying drawings, which illustrate one form of furnace made in accordance with my invention, Figure 1 is a side elevation, the furnace-casing being shown in section. Fig. 2 is a horizontal section on the line 2 2 of Fig. 1, and Fig. 3 is a horizontal section on the line 3 3 of Fig. 1.

Like marks of reference refer to similar parts in the several views of the drawings.

5 represents the fire-pot or combustionchamber. The fire-pot or combustion-chamher 5 is provided with a grate 6 and fire and ash-pit doors 7 and 8, respectively, all of the usual construction.

Connected with the combustion-chamber 5, adjacent to the top thereof, are two long descending fines 10 and 11, respectively.

12 and 13 are two short descending fiues, which are connected with the combustionchamber 5 at a point some distance below the top of the said combustion-chamber, as shown in Fig. 1.

The descending fines 10 and 12 and 11 and 13 form two sets of fines, which are connected by base-fines, the pipes 10 and 12 being connected bybase-fiue 14 and the pipes 11 and 13 being connected by a similar base-fine 15. The base-fines 14 and 15 communicate with ascendingfiues 16 and ]7, respectively. In order to equalize the draft in the descending fines, these ascending fines l6 and 17 are connectedto the base-fines 14 and 15 at points nearer to the long descending flues 10 and 11 than to the short fines 1'2 and 13, thus making the travel of the products of combustion equal in the long and short flues. The upper ends of the ascending fiues 16 and 17 are connected by means of a conduit 18, which passes over the short descending fines 12 and 13 and is connected with the outlet-pipe 19, which pipe passes through the usual f urnace-casing 20.

By using the longfiues 10 and 11 the products of combustion are drawn 0% near the top of the combustion-chamber, thus securing the proper circulation in the top of said combustion-chamber, and by using theshort fines 12 and 13 sufficient room is left for the passage of the conduit 18 without enlarging the furnace-casing 20, and by the connection of the pipes 16 and 17 the tendency to unequal draft between the long and short fines is overcome. I thus greatly increasethe radiating-surface of the fines and at the same time avoid enlarging the furnace-casing or disturbing the equal draft in the descending fines.

I am aware that it is old to provide a hotair furnace with two descending fines and two ascending fines, the ascending fiuesbeing connected with a suitable outlet-pipe, and therefore do not claim such construction.

Having fullydescribed my invention, what I claim as new, and desire to secure by Letters Patent of the United'States, is-

1. In a hot-air furnace, the combination with a combustion-chamber, of two sets of descending fines connected with said combustion-chamber, a base-fine connecting the pipes of one of said sets, a second base-flue connecting the pipes of the other of said sets, as cending fines connected with said base-fines, a cond nit connecting said ascending fiues,and an outlet leading from said conduit,

2. In a hot-air furnace, the combination with a combustion-chamber, of a pair of long I ing flues, and an outlet leading from said condescending fiues connected therewith, a pair duit.

of short descending flues also connected with In testimony whereof I have hereunto set said com bustion-chamber, a pairof base-fines my hand and affixed my seal in the presence 5 each connecting a long and a short descendof the two subscribing witnesses.

ing fine a pair of ascending flues each connected i vith one of said base-fines at a point CHARLES FOSTER nearer to the long than to the short descend- Witnesses:

ing flue, a conduit connecting said ascending J. H. BRYSON,

IO fines and passing above said short deseend- W. A. ALEXANDER. 

